#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
#define rep(i, a, b) for (int i = (a); i <= (b); i++)
#define per(i, a, b) for (int i = (a); i >= (b); i--)
#define endl '\n'
const int N = 25;

int n, m;
int f[N][N];

int main() {
  ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  cin >> n;
  n++;
  f[1][1] = 1;
  rep(i, 2, n) rep(j, 1, i) { f[i][j] = f[i][j - 1] + f[i - 1][j]; }
  cout << f[n][n];
  return 0;
}